Datasheet

I
IN -MAX
900mA
500mA
500mA
150mA
750mA
400mA
I
OUT
I
BAT
I
IN
TPS65070, TPS65072, TPS65073
TPS650731, TPS650732, TPS650701, TPS650702, TPS650721
www.ti.com SLVS950G –JULY 2009–REVISED MAY 2013
POWER DOWN
The charger remains in a power down mode when the input voltage at the AC or USB pin is below the under-
voltage lockout threshold V
UVLO
. During the power down mode the host commands at the control pins are not
interpreted.
POWER-ON RESET
The charger resets when the input voltage at the AC or USB pin enters the valid range between V
UVLO
and
V
OVLO
. All internal timers and other circuit blocks are reset. The device then waits for a time period T
DGL(PGOOD)
,
after which CHARGER ACTIVE Bit indicates the input power status, and the Iset pin is interpreted.
POWER-PATH MANAGEMENT
There are two inputs to the power path called AC and USB. Both inputs support the same voltage rating but are
typically set to a different current limit with AC beeing at the higher limit and USB at the lower. If voltage is
applied at both inputs and both are enabled in register PPATH1 (default setting), AC will be preferred over USB.
In this case, the deivce is only powered from AC and there is no current from USB. If voltage at AC is removed,
the USB input will become and TPS6507x is powered from USB. The current at the input pin AC or USB of the
power path manager is shared between charging the battery and powering the system load on the SYS pin.
Priority is given to the system load. The input current is monitored continuously. If the sum of the charging and
system load currents exceeds the preset maximum input current (programmed internally by I2C), the charging
current is reduced automatically. See the electrical characteristics or the register desciption for the default current
limit on AC and USB for the different family members.
Figure 26 illustrates what happens in an example case where the battery fast-charge current is set to 500mA, the
input current limit is set at 900mA and the system load varies from 0 to 750mA.
Figure 26. Power Path Functionality
SYS Output
The SYS pin is the output of the power path. When TPS6507x is turned off and there is no voltage at AC or
USB, the SYS output is disconnected internally from the battery. When TPS6507x is turned on by pulling PB_IN
=LOW, the voltage at SYS will ramp with a soft-start. During soft start, the voltage at SYS is ramped with a 30mA
current source until the voltage reached 1.8V. During the soft start, the SYS pin must not be loaded by an
external load.
BATTERY CHARGING
When Bit CHARGER ENABLE in register CHGCONFIG1 is set to 1, battery charging can begin. First, the device
checks for a short-circuit on the BAT pin: I
BAT(SC)
is turned on till the voltage on the BAT pin rises above V
BAT(SC)
.
If conditions are safe, it proceeds to charge the battery.
The battery is charged in three phases: conditioning pre-charge, constant current fast charge (current regulation)
and a constant voltage tapering-off (voltage regulation). In all charge phases, an internal control loop monitors
the IC junction temperature and reduces the charge current if the internal temperature threshold is exceeded.
Figure 27 shows what happens in each of the three phases:
Copyright © 2009–2013, Texas Instruments Incorporated Submit Documentation Feedback 25
Product Folder Links: TPS65070 TPS65072 TPS65073 TPS650731 TPS650732 TPS650701 TPS650702
TPS650721